This speaks to the movie I saw last night, 2018's "Leave No Trace." It's about a veteran with PTSD who can't stand to live on the grid, so he and his teenage daughter camp out in a park. He gets meds for his PTSD, which he sells for cash to buy supplies.
Myself, I'm really good at living cheap. That movie I watched last night? I checked it out of the local public library for free. I used to have big problems just getting by, couldn't hold a job for long in spite of everything I did. Competition for temp work around here was pretty fierce. I got by although I did get behind on my really cheap rent for a little while. Later I moved to a shared house where we had the cheapest rent I ever heard of... 6 of us. Sharing a house can be a lot cheaper than renting your own apartment.
I know a ton of tricks concerning frugal living (I should write a book). Most people spend way more money than they need to. Of course there are thrift stores. Garage sales, free boxes, public libraries that are free as long as you bring things back on time and don't get fines.
Yes, a bicycle is WAY cheaper than a car. No gas, no insurance. I went 20 years without a car! Didn't have a TV either, no time for that shit. I did all my own bike repairs. Bought a used bike! I've never bought a new bike in my life. Still ride a lot, it's good for the soul! I had one temporary job for a small local publisher and they let us pick books off of pallets to keep, seconds. A few of those were bike maintenance and etc. books. Working temps for 10 years was a struggle but I got to see and experience a lot of different things I never would have if I'd had a career during that period.
I became a do it yourself guy. Acquired tools one by one where ever. Found some I still have! I have a lot of basic hardware stuff in case I need to fix something or hey... improvise something (which can be fun)!
I eventually bought a used sewing machine... I still have and use occasionally.
Adequate nutrition is a challenge, but you can get by pretty cheaply if necessary.
Yeah, cheap rent is important if you're poor and don't want to be homeless.
Hey, man, good luck to you! Hang in there somehow.